Sometimes at the end of level 7 I have like 123 snouts counted, and another 4 or 5 on the screen, but still fall short of the 150 when all is counted plus a bonus, yet other times I will do the same calculation thinking I WILL fall short and make the 150 easily. It seems that the 'bonus' for completing level 7 is not constant. Additionally, when I have appeared to be close to whatever number I THINK will get me there, I have seen the last pig blowing up on my screen give 0 snouts...

There are a lot of people interested in an answer to this. I saw a player say (maybe on this very board) that they had gotten an answer from Rovio that indicated that the "bonus" number awarded after Level 7 was random. But it would be nice to have official confirmation. It certainly does not seem to be based on performance. Not only have I completed "perfect" runs - taking no damage and killing everything pretty quickly, but I have experimented with lots of other things too such as allowing Mama Pig to live and go through several spawn cycles to spawn extra pigs, etc. but nothing has worked to consistently get 150 snouts or greater.